Precision Measurements of Prompt Neutron Spectra in240Pu and242Pu Spontaneous Fission

Under the Program of Measurements of Prompt Neutron Spectra in Minor Actinides Fission for Transmutation Purposes carried out at the V.G. Khlopin Radium Institute the integral neutron spectra in the 240Pu and 242Pu spontaneous fission have been measured. The measurements were performed by the time-of-flight method in the energy range of 0.1-15 MeV relative to the standard neutron spectrum in 252Cf spontaneous fission. The accuracies of the average neutron spectrum energies are better than 2%. The theoretical computation of the prompt neutron spectra in the 240Pu and 242Pu spontaneous fission was performed in the framework of statistical approach using Hauser-Feschbach model.